Abstract: A silicon photonics-based optical modulator is disclosed. The optical modulator includes first radio frequency (RF) metal electrodes that operate as a ground, phase shifters disposed between the first RF metal electrodes for optically modulating an optical signal transmitted along an optical waveguide, second RF metal electrodes disposed between the phase shifters for providing an RF electrical signal received from a driving driver located outside of the optical modulator through one end, resistor-inductors (RL) connected to another end of the second RF metal electrodes, an inductive line disposed between the RLs and a power supply for applying a bias voltage to the optical modulator and the driving driver, and a silicon capacitor disposed between the RLs and the power supply for preventing a degradation of an RF response characteristic of the silicon photonics-based optical modulator caused by the inductive line.

Abstract: According one embodiment of the present disclosure, there is provided a silicon photonics-based optical modulation device having two metal layers. The optical modulation device includes a phase shifter, a ground unit, and a pad unit. The phase shifter includes a first signal electrode, a second signal electrode, and at least two ground electrodes formed in a first metal layer. The phase shifter includes two silicon optical waveguides. The ground unit is formed in a second metal layer different from the first metal layer. The pad unit is formed in the second metal layer, provided with a first local area electrically connected to the ground unit, and electrically connected to the first signal electrode and the second signal electrode via a second local area thereof electrically isolated from the ground unit.

Abstract: Disclosed are a terahertz signal generation apparatus and a terahertz signal generation method using the same. The terahertz signal generation apparatus includes first and second resonators configured to respectively output an optical signal of a first resonant frequency and an optical signal of a second resonant frequency from an optical signal input through a gain medium, an optical modulator configured to optically modulate the output optical signal of the second resonant frequency, an optical combiner configured to combine the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, and a signal generator configured to generate a terahertz signal using heterodyne beating between the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, wherein the first resonant frequency and the second resonant frequency are processed to have a predetermined frequency difference.

Abstract: A silicon photonics-based optical modulator is disclosed. The optical modulator includes first radio frequency (RF) metal electrodes that operate as a ground, phase shifters disposed between the first RF metal electrodes for optically modulating an optical signal transmitted along an optical waveguide, second RF metal electrodes disposed between the phase shifters for providing an RF electrical signal received from a driving driver located outside of the optical modulator through one end, resistor-inductors (RL) connected to another end of the second RF metal electrodes, an inductive line disposed between the RLs and a power supply for applying a bias voltage to the optical modulator and the driving driver, and a silicon capacitor disposed between the RLs and the power supply for preventing a degradation of an RF response characteristic of the silicon photonics-based optical modulator caused by the inductive line.

Abstract: A silicon photonics-based photodetector (PD) includes a silicon layer on which doped layers of different types are formed on a surface based on a first spacing based on a center line of an optical waveguide through which an optical signal moves, a germanium layer being stacked on an upper part of the silicon layer and formed with doped layers of different types on a surface based on a second spacing based on the center line of the optical waveguide, and a metal electrode configured to generate an electric field by being in contact with the doped layers of the silicon layer and the germanium layer.

Abstract: Disclosed is a silicon photonics-based optical transmission apparatus. The apparatus includes an optical modulator chip of a ground-signal-ground (GSG) electrode array including two phase shifters for differential driving, a sub-substrate including a metal electrode of a periodic pattern to connect two ground metal electrodes to each other at a GSG electrode connected to each of the two phase shifters, and a solder bump having a same periodic pattern as the metal electrode of the sub-substrate to connect the ground metal electrodes of the optical modulator chip and the metal electrode of the periodic pattern of the sub-substrate.

Abstract: An optical coupling method and apparatus are disclosed. The optical coupling method improve the speed of optical alignment between an optical fiber and a grating coupler (GC) of an optical coupling apparatus for a characteristic test of a silicon photonic integrated circuit (Si-PIC) chip by using a reflective grating couplers disposed on the Si-PIC chip.

Abstract: Disclosed is a silicon photonics-based optical transmission apparatus. The apparatus includes an optical modulator chip of a ground-signal-ground (GSG) electrode array including two phase shifters for differential driving, a sub-substrate including a metal electrode of a periodic pattern to connect two ground metal electrodes to each other at a GSG electrode connected to each of the two phase shifters, and a solder bump having a same periodic pattern as the metal electrode of the sub-substrate to connect the ground metal electrodes of the optical modulator chip and the metal electrode of the periodic pattern of the sub-substrate.

Abstract: Disclosed are a terahertz signal generation apparatus and a terahertz signal generation method using the same. The terahertz signal generation apparatus includes first and second resonators configured to respectively output an optical signal of a first resonant frequency and an optical signal of a second resonant frequency from an optical signal input through a gain medium, an optical modulator configured to optically modulate the output optical signal of the second resonant frequency, an optical combiner configured to combine the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, and a signal generator configured to generate a terahertz signal using heterodyne beating between the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, wherein the first resonant frequency and the second resonant frequency are processed to have a predetermined frequency difference.

Abstract: Disclosed is a silicon photonics-based electronic-photonic integrated circuit (EPIC). The silicon photonics-based EPIC includes a silicon photonic integrated circuit (PIC) chip in which an optical device is mounted on a silicon-on-insulator (SOI) wafer including a trench region, an electronic integrated circuit (EIC) chip mounted in the trench region of the PIC chip, and an electrical interface configured to connect an electrode pad of the PIC chip and an electrode pad of the EIC chip.

Abstract: A secure communication method and an apparatus performing the same are disclosed. The communication method includes receiving a signal encrypted based on at least one attractor and decrypting a security signal received using a neural network trained based on a training signal.

Abstract: An optical coupling method and apparatus are disclosed. The optical coupling method improve the speed of optical alignment between an optical fiber and a grating coupler (GC) of an optical coupling apparatus for a characteristic test of a silicon photonic integrated circuit (Si-PIC) chip by using a reflective grating couplers disposed on the Si-PIC chip.

Abstract: Wavelength channels used in the optical network system are classified into downstream channels used to transmit optical signals from an optical line terminal (OLT) to an optical network unit (ONU) and upstream channels that are used to transmit optical signals from the ONU to the OLT. The wavelength channels are included in an O-band and may not overlap each other. One of the upstream channels are allocated to a wavelength band (for example, a zero-dispersion window) in which a four-wave mixing occurs. A wavelength spacing between the upstream channels and the downstream channels is determined based on a performance of separating the upstream channels and the downstream channels in a bidirectional optical sub assembly (BOSA) of the ONU. Also, a wavelength spacing between the downstream channels is determined based on a performance of separating the downstream channels in the BOSA.

Abstract: A bidirectional optical element in optical network units (ONUs) of a passive optical network (PON) includes a main filter configured to pass an upstream signal having an upstream-channel wavelength and a downstream signal having a downstream-channel wavelength, a drop filter configured to pass the downstream signal having the downstream-channel wavelength and reject the upstream signal having the upstream-channel wavelength, and an add filter configured to pass the upstream signal having the upstream-channel wavelength and reject the downstream signal having the downstream-channel wavelength, wherein the main filter, the drop filter, and the add filter are configured to share a single optical waveguide, and the optical waveguide is configured to connect input ports of the main filter and the drop filter and an output port of the drop filter and is provided in a straight line shape.

Abstract: Wavelength channels used in the optical network system are classified into downstream channels used to transmit optical signals from an optical line terminal (OLT) to an optical network unit (ONU) and upstream channels that are used to transmit optical signals from the ONU to the OLT. The wavelength channels are included in an O-band and may not overlap each other. One of the upstream channels are allocated to a wavelength band (for example, a zero-dispersion window) in which a four-wave mixing occurs. A wavelength spacing between the upstream channels and the downstream channels is determined based on a performance of separating the upstream channels and the downstream channels in a bidirectional optical sub assembly (BOSA) of the ONU. Also, a wavelength spacing between the downstream channels is determined based on a performance of separating the downstream channels in the BOSA.

Abstract: A flexible printed circuit board (FPCB) for an optical module includes: a signal via pad connected with a signal lead pin of the optical module; a ground layer spaced apart from the signal via pad; an isolation gap formed between the signal via pad and the ground layer; and a protective layer which is formed at a portion that comprises the isolation gap, and which, when connected with the signal via pad, compensates for parasitic inductance caused by a protruding signal lead pin.

Abstract: Provided is a phase error compensating apparatus. The phase error compensating apparatus may include a waveguide array disposed between a first free propagation region and a second free propagation region and configured to allow a light signal passed through the first free propagation region to move toward the second free propagation region, in which a length of each of the waveguides included in the waveguide array may be adjusted to compensate for a phase error of light signals passed through the waveguides.

Abstract: Provided is a phase error compensating apparatus. The phase error compensating apparatus may include a waveguide array disposed between a first free propagation region and a second free propagation region and configured to allow a light signal passed through the first free propagation region to move toward the second free propagation region, in which a length of each of the waveguides included in the waveguide array may be adjusted to compensate for a phase error of light signals passed through the waveguides.

Abstract: An arrayed waveguide grating device and a method for manufacturing the arrayed waveguide grating device. The arrayed waveguide grating device includes input channel waveguides formed on a substrate; output channel waveguides formed on the substrate that correspond to the input channel waveguides; and arrayed waveguides with different lengths interposed between the input channel waveguides and the output channel waveguides on the substrate while free propagation regions being formed at both ends of the arrayed waveguides, wherein the arrayed waveguides are designed so that a free spectral range (FSR) of a higher-order mode is twice or greater than a bandwidth of a region of interest (ROI).

Abstract: A flexible printed circuit board (FPCB) for an optical module includes: a signal via pad connected with a signal lead pin of the optical module; a ground layer spaced apart from the signal via pad; an isolation gap formed between the signal via pad and the ground layer; and a protective layer which is formed at a portion that comprises the isolation gap, and which, when connected with the signal via pad, compensates for parasitic inductance caused by a protruding signal lead pin.